Pneumatic relay for automatic musical instruments.



A. W. LUNSDALE,

PNEUMATIG RELAY IOR AUTOMATIC MUSICAL INSTRUMENTS.

APPLICATION FILED APR.26,1909.

$44,798 Patented Dec. 28, 1969.

UNITED sTaTEs PATENT oEEjiioE.

ARTHUR WALTER LONSDALE. OF BEDFORD. ENGLAND.

PNUMATC RELAY FOR AUTUMATIC MUSICAL NSTRUMENTS.

` Specification of Letters Patent. Igiiintpd DCC, 28, 1909, Application tiled April 28, 1909.

Serial No. 492.175.

lioxsnALn, a subject of the Kinn' of Great Britain, and resident of 22 llf'oburn road, Bedford, 1n the county of Bedford, England, l

a member of the Burma Education Service, g have invented certain new and useful lmprovements in Pneumatic Relays Particularly Applicable for Use in Automatic Mii sieal Instruments, of which the following is a specification.

This invention relates to improvements in the construction of pneumatic relays, more particularly such as are commonly employed in the actions 7 of automatic piano-players and similar musical instruments or adjuncts thereto. As is well lniown s uch actions are devices for operating mechanical members whereby the corresponding note is caused to sound or any required impulse is produced, the working of the action being controlled by a pneumatic relay serving to establish or interrupt communication between (on the one hand) one of a series 0i' collapsible ele ments corresponding' to the .individual notes or impulses and (on thc other hand) a vacuunichest. wherein a substantially constant negative pressure is maintaiiied; each collapsible element normally containing` air at atmospheric pressure and being adapted, by the exhaustion consequent on its temporary connection with the common vacuum-chest, to transmit motion to the prolonge or equivalent member of the action appertains in il to the corresponding note or impulse. Theadmissii'ni of air to, or its exhaustion from, the collapsible clement determined by means of primary and seeondar f valves both of which are tloubli.- acting;- and whereof the latter (which has the larger movement and comn'iands passages of greater area) external atmosphere or with the vacuumchest. alternatively; the primary valve controlling'- such ii'iovement of theI secondary valve and being itself controlled in turn by the tunc-shcct passiiitg over holes m a. tracker board. Reliability and promptitude in acobviously of the utmost importance that the valves should be so constructed and nriinted as to be enabled to seat themselves .freely and with perfect accuracy in either of the two positions which each capable of assluiting, this` requirement bciip` more espeboard; serves to ptit the interior of thc collapsible t clement into direct communication with thc 1 end the valve is made rectangular, and is prt-.vented from excessive lateral displacenient (while being' left coii'ipletely free to seat itself fairly upon the surfaces with which it alternatively makes joint) by opposite lateral edges ot thel valve being attached to the adjacent sides of the valve chamber by means of a pair of loose flaps of very thin and flexible leather or equivalent mate rial.

For the salte of clearness, the invention will be described with reference to a conven broken away. Fig. 3 is a cross section on line oof Fig. l, and Fig. 4t is an enlarged View of partI of Fig. il.

Similar reference numerals denote corre spending parts throughouty the drawings.

l represents a portion of the vacuumchcst; 2 one of the small tubes which lead from the respective holes in the tracker'- the bellows which reprcscntthc collapsible elen'ieiitappertaining to the rc` lay; and Llthe rod through which motion is traiisinittcd from the [lap-board 5 ot' the bellows to the prolonge or eipiivalciit part o'l' the ii'icchanical action whereby the particular note or impulse is produced.

'l`lic pneumatic rela)v is comprised within the limits of a casing. preferably of rectan tion being essential in su ch apparatus, it. is

e'ular shape as indicated with which thc innclI end of thc vacuum chest makes an airtight joint. .l`he main portion olf'the interior of the casing constitutes a, vacuun'i-chaniber (i which is in direct and perinai'icnt comn'iunilatter; the partial vacuum or negative pressure existing in the chest being consequently maintained uniformly in this chamber.

The primary variable-pressure' chamber 8 is in permanent communication with the tracker-tube 2 which opens out through the face of the vacuum-chest 1. lVheu a hole in the tune-sheet registers with the tracker-hole, atmospheric pressure is admitted to the chamber 8 through the tube 2 so that the diaphragm 9 being in consequence distended upward, the valve-stem 10 is raised to its highest position, the lifting and dropping of the primary alve-stem occurring every time a perforation and the succeeding blank portion oi the tune-sheet respectively pass ove the tracker-hole.

The primary valve is duplex and when in the normal position as shown, the disk 11 closes the upper end of the valve stem hole,

` while the disk 12 leaves thelower end of the same open and thus maintains communication between the vacuum chamber 6 and the secondary variable-pressure chamber '13. Under these circumstances the diaphragm 15 is in equilibrium as regards the pressures to which its opposite sides are exposed, and is therefore lree to sag downward so as to permit the vertical stem 14 of the secondary valve to occupy tunderA gravity) its lowest position as indicated. When however, the primary valve-stein 10 is raised, the dish 12 closes the lower end ot the valve-stem hole while'the disk 1l leaves the upper end of the same open and thus admits atmospheric pressure to the chamber lp so that the diaphragm 15 is distended upward, the valvestem 14.- is raised to its highest position; the lifting and dropping ot' this secondary valve-stem occurring every time the primary valve-stem 10 is similarly raised and low` ered.-

The secondary valve is double-acting and consists of a flat piece 1G of wood or equivalent light material whose opposite surfaces are faced as at 17 and 18 with soft leather washers so as, according as the stem is in the normal (2'. e. the lowered) or in the raised position, to close air-tight an opening 19 in the lower wall 20, or an opening 21 in the upper wall 22 of the valve-chamber Q3 formed in the top board 24 of the casing. The chamber 23, which is of considerably larger area than the valve 1G which works in it, is in permanent communication by way of a passage 25, 20 with the interior of the bellows 3. Hence whereas, in the'normal position shown, the valve 16 closes the hole 19 and thus, by leaving the hole 21open, maintains atmospheric pressure within the bellows 3 whose flap-board 5 therefore remains down as does also the rod 4; on the other hand when the valve 16 is raised so as to close-the hole 21 and thus, by leaving the hole 19 open7 brings about the exhaustion of the bellows, the flap-board will be raised by the atmospheric pressure acting against its lower surface and will also raise the rod A l with the result that the corresponding note or impulse will be produced. T his eii'ect will obviously be produced each time a, perforation in the tune-sheet passes over the corresponding t1aclrer-hole.

The diaphragm 15 which is of thin and very flexible leather or like .nntteriah is preierably strengthened as usual by a central disk of stronger material as at 28 against which the lower end of the valve-spindle 1/1- bears. ln the case of the .secondary valve the length of lift is made adjustable, for which purpose the spindle 14?; may be constituted by a' screw working stily through hole in the valve, the head ot the screw being formed by a circular wooden button shed with-a disk of felt where it. rests upon the diaphragm 15.

T he chamber 23 is sunlt in the thickness ol the top-board Q42, its upper wall 225 which is removable so as to alilord access to the secondary valve 1G, being constitute hTVT a. thin board or the like jointed to thV p surface of the top-board 2li: eens i Washer 30 of soft leather or equiv terial and secured in place by screw:

As already stated, the feature of t tion consists in the fact o' the t valve being so mounted and guided t completely to seat i l" surlaces with which it alteri joint. For this purpose the sec: is made rectangular (prei-'fer shown) and 'is pi'.veiited lateral displacement lsucl; wise be permitted in consequence atively great width of the apertur 2l as compared with the d' n valve-stem lil) by opposite lateral the valve being attached to the au sides of the 'valve chamber 2?; l loose lapsBQ of very thin and l or equivalent material. Each llap is preteably secured to the valve by the curresponding end portion ot' the flap being lapped about a thin slip of wood which is then tightly wedged into a cut provided for the purpose in the edge oit 'the va indicated at 33 in^l1`im el, a pin vali/f' portions of the valves and the interior' of the relay from dust and insects. This cover 36 is shaped from a pieceI of sheet metal and' carriesA laterally two U-shaped flanges 37 adapted to slide into position along'a pair of "grooves or saw cuts 38 in the side of the top section 24 .of the casing of the relay and desire to secure by Letters each partlyv Iwedged in one of said recesses and each secured at l a side ofv lsaid valve chamber. g

2. In a pneumatic relay, a valve chamber,

'a valve movable therein and having grooves in opposite sides thereof, Hexible flaps, each grooves Wedgessecuring said4 parts in said secured to a side of said valve chamber, and each having' a partlocated 1n one of sald rooves, and. pins passing through the memer and said wedges.

ARTHUR WALTER LONSDALE.

`Witnessesz H'. D. JAMESON,

R. F. WILLIAMS. l 

